Boris Nemtsov, Putin foe, is shot dead in shadow of Kremlin
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The statement, the fullest official response so far to Mr. Nemtsov's killing, said the police were pursing half a dozen leads in the case, the highest-profile assassination in Russia during the tenure of Mr. Putin.
The committee also cited the possibility that Islamic extremists had killed Mr. Nemtsov over his position on the Charlie Hebdo shootings in Paris, saying that security forces had been aware of threats against him from Islamist militants. The committee also said that "radical personalities" on one or another side of the Ukrainian conflict might may have been responsible. The statement said the police were also considering possible business or personal disputes as motives.
"The investigation is considering several versions," the statements said. The first it listed was: "a murder as a provocation to destabilize the political situation in the country, where the figure of Nemtsov could have become a sort of sacrificial victim for those who stop at nothing to achieve their political goals."
This explanation echoed and elaborated on a statement posted overnight on the Kremlin website, which also characterized the murder as a "provocation."
"The president noted that this cruel murder has all the signs of a contract killing and carries an exclusively provocative character," the Kremlin statement said. "Vladimir Putin expressed his deep condolences to the relatives and loved ones of Boris Nemtsov, who died tragically."
Mr. Putin, in a message to Mr. Nemtsov's mother released by the Kremlin, said, "Everything will be done so that the organizers and perpetrators of a vile and cynical murder get the punishment they deserve."
Initially, Russian news media reported Mr. Nemtsov had been shot from a passing car. On Saturday, however, a television channel, TVTs, broadcast a surveillance video purporting to show the murder, though from a distance. Mr. Nemtsov had left a restaurant in the GUM shopping center on Red Square and was walking with his girlfriend, Anna Duritskaya, a Ukrainian model.
A snowplow blocked the scene. But the video, which has not been independently verified, appears to show the shooter was hiding on a stairway on Moskvoretsky Bridge waiting for Mr. Nemtsov and Ms. Duritskaya to pass. Later, the figure of the supposed shooter runs to a getaway car that pulls up on the bridge.
After laying flowers on a floral mound already chest high and kneeling in respect before the blooms festooning the sidewalk on a rainy, glum midafternoon, Anatoly Chubais, a co-founder with Mr. Nemtsov of the Union of Right Forces political party, scorned the investigators' claim.
"Today, we had a statement that the liberal opposition organized the killing," he said. "Before this, they wrote that the liberals created the economic crisis. In this country, we have created demand for anger and hate."
Ilya Yashin, a political ally of Mr. Nemtsov's, drew attention again to the pamphlet Mr. Nemtsov was preparing on Russian military aid to pro-Russian rebels in Ukraine. Speaking on the Echo of Moscow radio station, he said Mr. Nemtsov had "some materials that directly proved" the participation of the Russian army in the Donbas war in Ukraine.
Mr. Yashin said he knew no details, or what had become of those materials.
Ms. Albats, who had discussed with Mr. Nemtsov his unfinished exposé, said of this state of affairs in domestic Russian politics, "We are at war now."
"Those who are believers in democracy, those who for some reason, back in the late 1980s, got on board this train, and had all these hopes and aspirations," she said, "they are at war today."
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